Accelerating fully phase-encoded MRI near metal using multiband radiofrequency excitation.

Autor: Artz NS; Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.; Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee, USA., Wiens CN; Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA., Smith MR; Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA., Hernando D; Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA., Samsonov A; Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA., Reeder SB; Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.; Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.; Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, USA.; Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA.; Department of Emergency Medicine, University of Wisconsin, Madison, Wisconsin, USA.
Jazyk: angličtina
Zdroj: Magnetic resonance in medicine [Magn Reson Med] 2017 Mar; Vol. 77 (3), pp. 1223-1230. Date of Electronic Publication: 2016 Mar 28.
DOI: 10.1002/mrm.26209
Abstrakt: Purpose: To develop a multiband radiofrequency (RF) excitation strategy for simultaneous excitation of multiple RF offsets to accelerate fully phase-encoded imaging near metallic prostheses.
Methods: Multiband RF excitation was designed and incorporated into a spectrally resolved fully phase-encoded (SR-FPE) imaging scheme. A triband (-6, 0, 6 kHz) acquisition was compared with three separate single-band acquisitions at the corresponding RF offsets with a phantom containing the head of a hip prosthesis. In vivo multiband data with continuous spectral coverage were acquired in the knee of a healthy volunteer with the head of a hip prosthesis placed posteriorly and in a volunteer with a total knee prosthetic implant.
Results: Phantom images acquired with triband excitation were essentially identical to the composite of three single-band excitations, but with an acceleration factor of three. In vivo multiband images of the healthy knee with adjacent metal demonstrated very good depiction of knee anatomy. In vivo images of the total knee replacement were successfully acquired, allowing visualization of native tissue with far less signal dropout than 2D-FSE.
Conclusions: FPE imaging with multiband excitation is feasible in the presence of extreme off-resonance. This approach can reduce scan time and/or increase off-resonance coverage, enabling in vivo FPE imaging near metallic prostheses over a broad off-resonance spectrum. Magn Reson Med 77:1223-1230, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
(© 2016 International Society for Magnetic Resonance in Medicine.)
Databáze: MEDLINE
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